Google This is a digital copy of a book lhal w;ls preserved for general ions on library shelves before il was carefully scanned by Google as pari of a project to make the world's books discoverable online. Il has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one thai was never subject to copy right or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books are our gateways to the past, representing a wealth of history, culture and knowledge that's often dillicull lo discover. Marks, notations and other marginalia present in the original volume will appear in this file - a reminder of this book's long journey from the publisher lo a library and linally lo you. Usage guidelines Google is proud lo partner with libraries lo digili/e public domain materials and make them widely accessible. Public domain books belong to the public and we are merely their custodians. Nevertheless, this work is expensive, so in order lo keep providing this resource, we have taken steps to prevent abuse by commercial panics, including placing Icchnical restrictions on automated querying. We also ask that you: + Make n on -commercial use of the files We designed Google Book Search for use by individuals, and we request thai you use these files for personal, non -commercial purposes. + Refrain from automated querying Do not send automated queries of any sort lo Google's system: If you are conducting research on machine translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the use of public domain materials for these purposes and may be able to help. + Maintain attribution The Google "watermark" you see on each lile is essential for informing people about this project and helping them find additional materials through Google Book Search. Please do not remove it. + Keep it legal Whatever your use. remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other countries. Whether a book is slill in copyright varies from country lo country, and we can'l offer guidance on whether any specific use of any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner anywhere in the world. Copyright infringement liability can be quite severe. About Google Book Search Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers discover the world's books while helping authors and publishers reach new audiences. You can search through I lie lull lexl of 1 1 us book on I lie web al |_-.:. :.-.-:: / / books . qooqle . com/| nma*frY£j£7 V~ -•. # ■» *. X 3 i s \ li fa* /3 BULLETIN No. 18. U. S. DEPARTMENT OF AGRICULTURE. DIVISION OF FORESTRY. EXPERIMENTAL TREE PLANTING IN THE PLAINS. CHARLES A. KEFPEH, Assistant Chief of the Division. WASHINGTON: I CONTENTS. Pace. Introduction 9 Conditions affecting tree growth 10 Heat 11 Light 13 Moisture 17 Soil and soil moisture 18 Atmospheric moisture 20 Selection of species * 21 Introduction of exotic trees 23 Hardiness 25 Rules for mixing species 26 Pure plantings 27 Mixed plantings 28 Nurse trees 28 The use of evergreens in Western planting 32 Experimental plantations 34 Objects 36 Botanical list of trees used in the planting experiments 37 Coniferous species 37 Broad-leafed species 37 Kansas 38 Underplanting 38 Planting in grass 40 Field planting ^. 40 Plats planted in 1897 41 Notes on the Kansas plats 45 Nebraska 47 Plantings of 1896 47 Plantings of 1897 54 Notes on Nebraska plantings 58 Colorado 60 The planting of 1896 60 South Dakota 63 Location and soil 64 Rainfall '. 64 The planting of 1889 64 The planting of 1890 69 Plantings of 1896 71 Plat planting 72 The planting of 1897 77 Utah 78 Growth of trees planted at Logan 86 Minnesota 87 Crookston plantation * 87 Grand Rapids plantation 87 Experiments with nurseries for evergreens 89 Evergreens from seed 91 Directions for evergreen seed bed 91 5 ILLUSTRATIONS. PLATES. Paga Plate I. Nebraska plantation, Plat 1 (Frontispiece) . II. Nebraska plantation, Plat 2 52 III. Colorado plantation 60 IV. Fig. 1. Scotch Pine in South Dakota plantation. Fig. 2. South Dakota plantation 64 V. Utah plantation 78 TEXT FIGURE. Fig. 1. — Diagram of underplanting in Kansas 39 6 INTRODUCTION. Forestry has to deal with forests. Forests subserve two purposes : supply of a most necessary raw material, and amelioration of the con- ditions of climate and water flow. In the semiarid and arid regions not only is tree growth established with more difficulty and expense, but except where irrigation can be had in full supply the trees will grow slowly after the vigorous juvenile period of twenty or thirty years, and remain of small dimensions, short bodied, and fit only for firewood. Protection, then, amelioration of climate, is the principal object of forest planting in these regions. Wood supply is the secondary con- sideration. The forests which furnish the enormous quantities of wood material used in this country, amounting in value to $1,000,000,000 in round numbers per year, grow in the humid regions, and will always grow there, because they are more favorable to tree growth, developing larger and better timber, more rapidly and cheaply, and that, too, on nonagricultural soil. The first interest, namely, our lumber supply, being so infinitely more important, most of the attention of the Division of Forestry was immedi- ately taken up with problems affecting the rational use of our existing forest resources and their recuperation, somewhat to the exclusion of the questions which interest the tree grower of the West. The only way in which the division could have made itself useful in the latter direction seemed to be in field demonstration, namely, by establishing experimental plantings in which the adaptation of species to the climate and methods of using the same might be tested and object lessons exhibited. Practical difficulties of various kinds and deficiency of funds prevented the inauguration of such work until a plan of cooperation with the State agricultural experiment stations removed at least a part of these difficulties, and the abandonment of other important work furnished sufficient means to attempt this field work. This has now been carried on for three years under many draw- backs, the most detrimental of which is the difficulty of securing properly selected satisfactory plant material delivered in good condi- tion, and of adequate personal superintendence at the various stations during planting time. While the professors of horticulture who have kindly volunteered to take charge of these plantations unquestionably devote themselves 7 8 to this voluntary duty as zealously as to any other, and have our sin- cerest thanks for their interest in the same, we are aware that, espe- cially at the planting season, they are so overcrowded with work that only a passing attention can be given to this outside matter; and at the same time wherever directions for field work are to be given from a central office far away from the 10 or 12 stations, all differently situ- ated climatically, the full measure of success can not be expected. The difficulties surrounding the procurement of plant material have been discussed at length by Mr. Keffer in this report. The objects of these experimental plantings may be briefly stated as follows : 1. Testing adaptability of various native and exotic species in the several regions. 2. Finding methods of establishing such species as seem well adapted, but are difficult to start. 3. Testing the behavior of various species in mixture, and their influence upon one another, as a basis for selecting proper mixtures (mixed planting being recognized as superior). 4. Developing methods of cultivation, more successful or cheaper than those in use. 5. Finding methods of securing plant material most cheaply. 6. Testing influence upon hardiness of locality from which the seed is secured. 7. Demonstrating forestry methods in tree planting. In spite of the difficulties mentioned, the experiments have been fairly successful and instructive and will become more so as the trees grow. Nor should it be overlooked that, in experiments, failures are just as instructive — provided their cause is discovered — as successes. More liberal appropriations to place this work upon an adequate basis, commensurate with the interests involved, would produce more satisfactory results. B. E. Febnow, Chief Division of Forestry. EXPERIMENTAL TREE PLANTING IN THE PLAINS. INTRODUCTION. An effort has been made in this bulletin to bring together a record of experimental plantings, not yet sufficiently extended to be more than suggestive, which have been conducted by tho Department of Agriculture during the last two years. It seemed in this connection desirable to give also a brief discussion of conditions affecting tree growth, with special reference to those encountered in the Western plains, where the plantations are mostly located. The forestless region of America includes all the States between the Mississippi River north of the Ozark Mountains and eastern Texas, and the Eocky Mountains, together with the plateau west of the Rocky Mountains. The possibilities of forest growth in this vast area are yet to be proved. Roughly speaking, any species that thrive in the adjacent wooded regions can be grown in Iowa, the Red River Valley of Minnesota and North Dakota, the Sioux Valley of South Dakota and the eastern counties of Nebraska, and in the more southern States. We know that difficulties of cultivation increase rapidly as one goes westward, but we can not say where the western limit of successful tree culture is. We can not even define the limits of successful agri- culture in the plains, for with increased facilities for irrigation splen- did crops are now produced where only a few years ago it was thought desert conditions would forever prevail. It is admitted that forest planting, as a financial investment, will probably be profitable on the plains only in a limited degree. Favor- able sites may enable the profitable raising of fence posts and other specialized tree crops, but the growing of timber on a commercial scale can hardly be expected. The quick and sure returns of agricultural crops warrant the farmer in supporting expensive irrigation works in the semiarid West, but we can hardly foresee a time when even an approximate expenditure for the maintenance of a forest crop would prove profitable except for the protection afforded by it. While this is probably true, there yet remains for demonstration the limitations of tree culture within the possibilities of the Western farmer-^-what spe- cies are adapted to his land; what methods give promise of success; what can he do to improve conditions and so make possible not only the growth of useful timber, but ttlso a greater variety of agricultural operations. As has been intimated, the difficulties of tree growing 9 10 increase greatly as one proceeds northward and westward from the eastern forest area. In the eastern border of the plains the planter has almost as great latitnde in his choice of varieties as has the dweller within the forest, and he may select timbers of the highest economic value, choosing several kinds, each adapted to specific uses, and plant- ing with them others whose only purpose is to promote the growth of his select trees. As we go westward the possibilities of choice become more and more restricted, until in western Kansas and Nebraska, in the upper Missouri Valley and the high plains of Texas, New Mexico, and Colorado very few species can be relied upon, and these will have to be nurtured and cared for to a degree not dreamed of by the East- ern farmer. The exact limits of choice have yet to be determined. Thus far we must deal largely with generalities and inferences, which become more and more problematical as we proceed westward. The experimental plantings herein described in detail are given not only as a record of the beginnings of an important work, but as indi- cating what are believed to be useful mixtures of trees for planting in the West. Sufficient time has not elapsed, even in the oldest plantings described, for final conclusions to be drawn; but the notes on kinds will be found of interest in connection with the experiments, and the whole is believed to afford a basis for selection of trees for the various States included in the treeless area. While this bulletin has to do primarily with Western planting, it may be found a safe guide in many directions for forest planting within the timbered regions of the country, especially as to general principles involved. Experiments in planting in cut-over lands in the pineries of Minnesota and Pennsylvania have been begun by the Department, but are not yet sufficiently advanced to warrant even a progress report. CONDITIONS AFFECTING TREE GROWTH. In common with all plant life, trees require a certain amount of heat, light, and moisture for their development. These elements are so inter- dependent in their effect upon tree growth that it is almost impossible to consider one without keeping in mind the influence which the other two are constantly exerting. Thus, if we discuss the effect of heat upon tree growth, we are at once reminded that the action of heat and light are inseparable and that the result upon the same species in a moist and a dry region is quite different. It must be remembered that these elements are never dissociated in their influence on plant growth. Most trees have a wide range of endurance of heat, light, and mois- ture. The Red Cedar is a striking illustration of adaptability to a great range of conditions. It is found in the swamps of southern Florida, furnishing wood for pencils; on the dry, exposed foothills of the Eocky Mountains, where it is reduced to a mere shrub; along the Platte Eiver Yalley in Nebraska, in the northern forests of Maine, and reaches its best development in the limestone soils of eastern Tennessee — an 11 immense range of conditions, illustrating well the possibility of adap- tation which a single species may have. All species possess to a greater or less degree the power of with- standing varying conditions, but for each there is an ascertainable degree of heat (and presumably of moisture and light) at which it grows best. In tree culture the character of the soil is important principally (one might say only) in so far as it affects the amount of moisture and heat available for the trees; and the lay of the land — exposure — is also to be considered principally with reference to heat, light, and moisture. HEAT. The heat requirement of plants in the open can be controlled to only a slight degree by the cultivator. He may frequently guard against frost by care in the selection of a site for the plantation, and the evil effects of hot winds may sometimes be avoided in the same way; but this is less true in the plains, where there are relatively smaller differ- ences in the elevation of the land than within the forested area. As a rule, species must from the first be sufficiently hardy to with- stand the extremes of heat and cold to which they will be subjected where planted. Hardiness is usually regarded as the ability of a species to withstand cold, but it is quite as important to consider also its heat resistance. The Butternut (Juglans dnerea) is not generally hardy in the plains, though native along the streams of Iowa and Minnesota as far north as Minneapolis. It suffers from sun scald in plantations, and hence can not be considered hardy. The Catalpa and Russian Mulberry, while successful in eastern Kansas, fail in the west- ern part of that State in much the same way that they do in northern Nebraska, though the winter climate in western Kansas is but little, if any, colder than that of the eastern part of the State. Light and moisture evidently have an influence in determining hardiness, as well as heat; in this, as in the rate of growth, all three factors are important and can not be dissociated. Classified with regard to their ability to endure cold, the species usually available for planting in the West would stand about as follows, the hardiest being named first: First group. — Aspen, White Spruce, Yellow Birch, Sweet Birch, Jack Pine, White Pine, Red Pine, Norway Spruce, Red Cedar, Scotch Pine, Austrian Pine, White Elm, Cottonwood, Boxelder, Green Ash (for North Dakota and northern Minnesota). Second group. — Rock Pine (Bull Pine), Douglas Spruce, Hackberry, White Willow, Black Cherry, Bur Oak, Red Oak, White Ash, Silver Maple (for South Dakota and northern Nebraska). Third group. — Chestnut, Black Walnut, White Oak, Cow Oak, Hick- ory, Honey Locust, Kentucky Coffee Tree, Black Locust, Catalpa, Russian Mulberry, White Fir (for south Nebraska and Kansas). Fourth group. — Pecan, Osage Orange, Shortleaf Pine, Mesquit, Chinaberry (for Oklahoma and Texas). 12 Many of the more northern forms named, though not all, will succeed in the more southern localities. Many more species, both native and introduced, may occur to the reader, but these have come within the observation of the writer and are classified from this standpoint. It must be remembered that light and moisture conditions will greatly influence the action of species, as well as resistance to cold. In general, it may be expected that as one goes westward the conditions affectiug growth are more severe, so that species which succeed in the eastern part of the plains may fail entirely in eastern Colorado. Trees that are not quite hardy while young can sometimes be grown where success would otherwise be impossible by planting them among others of a larger size which may have been set a few years previously, thus affording a slight protection for the more delicate kinds. Several of our most useful species are thus subject to injury from frost during their infancy, becoming quite hardy after the first few years. Even the hardiest species will occasionally suffer badly or be entirely killed by late frosts. At Brookings, S. Dak., almost all the European Larch trees in a plat numbering several hundred were killed by a heavy frost after the leaves were one-third grown. The trees which survived required two years to recover their normal condition. Frost injury to foliage is common to all species in the Northwest, where even the Aspen is not exempt in early spring before the young growth becomes hardened. A lack of heat affects the growth of trees principally in dwarfing them where they are not killed outright. The Eussian Mulberry, which is little more than a shrub in the southern counties of South Dakota, where it is always killed back in cold winters, becomes a good-sized tree in the Arkansas Valley. Bur Oak, one of the largest of its genus as grown in Kentucky and Missouri, presents a stunted appearance in the forests of Minnesota. On the other hand, it has been observed that the Boxelder as grown at Yankton, S. Dak., is larger and more vigorous than the same species at Hutchinson, Kans. The trees in both sites are in bottom land where they have a plentiful supply of moisture. This indicates that too much heat may have a dwarfing tendency the same as insufficient heat. This dwarfing may be turned to good advantage by the grower in his selection of species for mixed planting. Usually in the choice of nurse trees a species is selected that will grow rapidly during the first few years, so as the better to protect the youth of its more delicate nurslings, and then more slowly, so that the protected trees may forge ahead and have the full benefit of all the light for their crowns. It will be for such secondary species only that advantage can be taken of the effects of cold upon the tree growth, and even here other kinds can be found which are not thus harmed, and would presumably be equally good for the purpose in view. 13 It should be said that too much heat is quite as objectionable as a too low temperature. Of species not adapted to high temperatures the Boxelder, Aspen, Yellow and Sweet Birch, the Spruces, Larches, and Northern Pines and Hemlock may be mentioned. LIGHT. It may be safely assumed that all species of trees make their stron- gest growth when in the enjoyment of full sunlight, quite free from the shade of their fellows. While this is true, certain species can endure more shade than others, some even being able to pass their entire lives in comparatively dense shade. Almost if not quite all trees can withstand more shade during the first few years of their lives than subsequently; indeed, to some, notably the conifers, such protection is necessary during their infancy. This variability in the amount of shade a species can withstand has given, rise to the expressions " light demanding," applied to trees which require full light for their develop- ment, and " shade enduring," which are species that can grow for a longer or shorter period in the shade of others. The Cottonwood and the Scotch Pine are good examples of light-demanding trees, and the Beech and Hemlock of shade enduring. The relative amount of light required by a species changes with heat and moisture; thus in a moist, warm soil an increased amount of shade may be endured and permit the assimilation of the greater amount of food available. One may have striking examples of the interrelation of heat, light, and moisture in the storage of such ornamental plants as the Oleander through winter. These plants are grown in large pots or tubs, and they may be safely kept in a comparatively dark, cool cellar, if at the same time they be given but very little water. If too much moisture be given, the plants will rot, and if they be kept too warm a long spindling growth will result that will weaken the plant almost beyond recovery. If the storage room be light, an increased amount of both heat and moisture will be necessary to keep them healthy. Because certain species, such as the flowering Dogwood, Beech, Sugar Maple, and Hemlock of the Appalachian region, are found to endure for long periods in the shade of other trees, like the oaks and pines, it must not be assumed that the shade is necessary to their best growth. Neither is it a reasonable inference that the Hemlock can be grown only in the shade because of the disastrous effect upon Hemlock of the removal of associated species. In this case it is the sudden increase of light and the inability of the species to adjust itself to new conditions that frequently results in the death of the Hemlock. Were the pines and hardwoods thinned out gradually, affording a slow change extend- ing over a period of years, the Hemlocks would doubtless be benefited by the increased light. 14 Hemlock is much more influenced by moisture conditions than by light, and it seeks northern slopes more because of their moisture than because of their coolness. In a number of city parks where the Hem- lock is grown in isolated specimens as an ornamental tree the fact that it succeeds admirably in full sunshine is thoroughly established. So, too, isolated specimens of the flowering Dogwood, the Beech, and other shade-enduring species prove that these trees are able to endure shade better than their fellows, not that they thrive lesa well in full light. When trees of equal light requirement are planted together the struggle for light among them results in more rapid thinning than where light-demanding and shade-enduring species are mixed. If the single kind used be light-demanding, weeds and grass soon gain a foot- hold and rob the soil of much of the moisture which otherwise would be saved to the trees. Illustrations of this are common in the Cotton- wood plantations of the West. The Cottonwood is a thin-foliaged, light-demanding species, which does not shade the soil enough to pre- vent grass growth even where planted close. I have seen plantations of it in South Dakota where the trees were 40 feet high, and culti- vation was still necessary to keep the weeds down and conserve the soil moisture. In making a grove or plantation, varieties of different light require- ment should be mixed together, and varieties of equal light requirement should not be mixed. Illustrations of this law abound in wild growths. The Sugar Maple and the Beech are shade-enduring trees, and through- out the Northeastern States they will be found growing well in the shade of such species as White Ash, Black Walnut, and the Oaks and Birches. In even greater degree Hemlock is shade-enduring and is usually found as a lower growth, or " second story," with White and Bed Pine towering above. In the West the only native woods occur along the streams, and the difference in light requirement is less pronounced than in the heavily forested region. All trees there seem more intolerant of shade. Pos- sibly there are fewer cloudy days and the woods are more open, thus surrounding the trees throughout life with more light. But even in the Western woodlands a difference in light requirement is apparent and may be used advantageously by the planter. The Boxelder, Mul- berry, and White Elm withstand shade better than the Black Walnut, Green Ash, and Black Locust. The Red Cedar, White Fir, and White Spruce endure more shade than the Pines. The change in light requirement that comes with age is of great practical importance to the planter, as it enables him to provide shelter necessary in youth to certain species which are, nevertheless, intolerant of shade as they approach maturity. The Bur Oak is decidedly a light- demanding species, but during the first ten years it may be safely sur- rounded by dense-foliaged neighbors, and, indeed, it will be benefited for an even longer period by receiving light only directly overhead. 15 Erect growth will result, with very few lateral branches, thus forming from the first the clean, straight trunk so necessary to high quality in timber. The Gatalpa, though not a shade-enduring tree, retains its lateral branches with such persistence as to require dense-shading nurses to assist it in shedding them. The Scotch Pine, when grown in full sun- shine and with plenty of room, as in parks or lawns, seldom forms a straight trunk, but usually divides into heavy branches near the ground, thus making its timber of little value. Close-shading neigh- bors will correct this fault and result in a straight stem, from which the lower laterals soon fall. Care must be exercised with all the heavy- branched conifers, such as the Scotch, Austrian, Bock (Bull), and Eed Pines, not to overtop them with shading trees. They are benefited by side shade, aud even that must be reduced as the trees advance; but they are intolerant of shade overhead. The White Pine will endure more shade during youth than the heavier branched Pines named, but it also requires unobstructed light at the top after, say, seven to ten years, and needs full sunshine as it approaches maturity. Indeed, as was said at the beginning of this chapter, all trees are benefited by full light, viewed from the standpoint of growth. When the use to be made of their timber is considered, however, it may be added that all trees will profit by the formative influence of close plant- ing with shading neighbors that will prevent the light from reaching the lower branches as the trees develop. In the absence of light the foliage is unable to do its work, the branches die from lack of nourish- ment, and within a few years fall away. The upper part of the crown, meanwhile, is elongated in an effort to reach full light, and thus the stem grows straight and tall, and all the wood laid on the trunk is free from knots. After the stem is well formed additional light should be given the best trees by thinning out the inferior species or specimens, and thereafter increased volume growth will result. Relative height growth. — In determining rules for mixed planting, the effect of light upon tree growth is intimately associated with the relative height growth of various species. Not only has each species an average height in maturity, enabling us to make a classification on this basis (White Pine, Tulip, and White Oak being high trees as compared with Boxelder and Mulberry, or Wild Plum and Scarlet Haw), but the growth in height is much greater at one period than at another. Generally speaking, all species make their principal height growth during the earlier part of their lives, the increase in volume of usable material being greater thereafter. But during this time of rapid height growth there is much diversity in the action of species. The White Spruce is very slow in growth during the first years, and its growth thereafter, though much more rapid, never equals that of Scotch and White Pine. The Colorado Blue Spruce is much slower than White Spruce at all stages of its development. As 16 observed in nurseries in the lake region, the Douglas Spruce requires about ten years in which to form a leader, during which time it will have grown about 2 feet high; thereafter it resembles the Norway Spruce in its development. Red Cedar grows well from the first, though never a rapid grower as compared with White Pine at its best. Among the pines that seem especially adapted to the plains the Rock (Bull) Pine is a very slow grower during the first five years and seems never to make as rapid height growth as the Scotch Pine. Scotch and Austrian Pine are similar in growth, the Scotch being a little more rapid; both are better growers than either Eock or White Pine during infancy, but the White Pine under favorable conditions surpasses them at its most rapid period of growth. The White Pine grows slowly in its wild state for the first seven years, then with increasing rapidity to about the thirtieth year, then more slowly, but still at a good rate, to about the eightieth year, by which time the principal height growth will have been attained. The Bur Oak is likewise slow up to about the tenth year, and it never grows as rapidly in height as does the White Pine at its best, but it is a persistent grower over a long period. The Green Ash is a tree of comparatively slow growth, but it maintaius about the same rate from the first until it has made its principal height growth. The White Elm is more rapid than Ash or Oak during its first years, and it also continues a vigorous height growth until it approaches maturity. The Cottonwood is a very rapid grower from the first until maturity, as short-lived trees are apt to be. The Box- elder grows with great rapidity until 5 or 6 years of age, and makes its principal height growth by the thirtieth year. It is a medium to small tree when mature. The Catalpa and Black Locust are among the most rapid growing trees during the first few years from seed, but after the tenth year they grow much more slowly, being surpassed thereafter by White Elm. Black Cherry is a rapid and continuous grower, almost equal to the White Elm. Russian Mulberry grows very rapidly the first few years, making many branches and being thus an exceptionally good soil cover. Its period of rapid height growth is about the same as the Boxelder, and like that species it is a medium- sized tree. Silver Maple is a rapid and continuous grower for the first twenty-five years, when it usually begins to fail in close plantation. Black Walnut is somewhat more rapid in growth than Green Ash dur- ing the first few years from the seed. At ten to fifteen years Black Walnut will usually equal Boxelder in height, and in favorable soils it has attained a height of sixty feet in twenty-five years, though such rapid growth is exceptional. Honey Locust is a more moderate grower than Black Locust, but fully equals the White Elm and is of similar habit. These notes, made from observations in Nebraska, Iowa, and South Dakota, may not apply with even approximate truth in the Southwest, where the conditions are very different, but they will serve to call 17 attention to an important point in providing the proper light require- ment of trees in mixed planting. Such species as Boxelder and Rus- sian Mulberry, which endure more shade than most of the broad-leafed trees that have been tested in the West, by virtue of their compara- tively rapid height growth during the first few years, are especially useful as nurse trees, among which other species of more continuous height growth may be set. If the latter be light-demanding they will have overtaken their nurses before much damage can befall them (since all species endure somewhat more shade in infancy than when older), and if they be shade-enduring they will, by their habit of continuous growth, surpass their nurses and thus come into better light conditions as they develop. The shade endurance of trees is probably less in the plains than within the forest area. A list of trees most likely to succeed in the for- estless region, grouped with reference to their light requirement, is given below, the most light-demanding being named first. The rank- ing is only tentative, and further observations may modify it somewhat, but it is believed to be sufficiently accurate to stand as a basis for determining what species may be planted together: 1. Cottonwood, Aspen, Mesquit, Black Locust. 2. Scotch Pine, Austrian Pine, Rock or Bull Pine, Green Ash, White Ash, Black Walnut, Yellow Birch, Sweet Birch, Black Birch. 3. lied Oak, White Oak. Bur Oak, Tulip, Pecan, Honey Locust, Chestnut. 4. Jack Pine, Catalpa, Silver Poplar, White Elm, Black Cherry, Silver Maple, Osage Orange. 5. Hackberry, Red Maple, Boxelder, Russian Mulberry. 6. Sugar Maple, Beech, Norway Spruce, White Spruce, Douglas Spruce, Red Cedar, White Fir, Hemlock. Of these groups the first two may be considered light-demanding trees, and the last two shade-enduring, leaving the third and fourth groups midway, but with considerable shade endurance in youth. In making selections from this list, hardiness and moisture require- ment must be kept in mind as well as light conditions and relative height growth. MOISTURE. It has often been claimed that the absence of trees from the plains is attributable to a lack of sufficient moisture, and were it not that so many artificial plantations are growing in what was only a lew years ago a treeless region, the hypothesis might be accepted. But when it is recalled, also, that even in the States of Illinois and Iowa, with an average rainfall of from 44 to 32 inches, vast areas were devoid of trees, the theory of itself will not stand. The minimum amount of moisture necessary for the support of forest growth can not be definitely stated, because other conditions can not 20191— No. 18 2 18 be dissociated from tbe moisture requirement, atmospheric movements and soil character being the chief of these. It may be safely assumed that the line of successful tree culture will be moved westward in even pace with the agricultural development of the country, and but little, if any, in advance of it. The clay soil of the plains, protected with but a scant growth of herbage, undisturbed through centuries beneath the burning 6un and almost constant wind, compacted by the hoof beats of countless buifalo, can not be as absorbent as it will be when the plow has turned it, and frost has disintegrated it, and the deep growing roots of alfalfa have made it permeable to moisture. Wherever large areas have been brought into cultivation, tree culture has been more successful than before the advent of the plow. The prairies of Illinois, Iowa, and the eastern parts of Kansas and Nebraska with their planted groves fully sustain this view. The area of successful tree culture in the West can be demonstrated only by test plantings. Even should failure attend these at first, it must be borne in mind that the methods employed or the material selected may be responsible for the results quite as much as any lack of moisture. In the past two years, since the planting experiments herein recorded were begun, the rainfall during the growing season, March to October, at Manhattan, Kaus., has been for 1896, 34.24 inches, quite evenly distributed throughout the season; for .1897, 20.51 inches, with only 1.4 inches in August and September. The average rainfall at this station for the months March to October, inclusive, for the past forty years has been 24.02 inches, distributed by months as follows : March, 1.32 inches ; April, 2.78 inches ; May, 4.08 inches ; June, 4.46 inches $ July, 4.65 inches; August, 3.52 inches; September, 2.95 inches; October, 2.26 inches: an amount which both in quantity and distribution would lead one to anticipate, what experiments thus far indicate, suitability of soil moisture for quite a number of varieties of trees of the Eastern forest region. At Lincoln, Nebr., the rainfall for the same period in 1896 was 24.22 inches, and in 1897, 21.73 inches, and a reference to the record of growths at that station (see page 59) indicates this to have beenitmple for the needs of most of the species tested. At Brookings, S. Dak., the rainfall for the same period in 1896 was 19.1 inches, and for 1897, 20.55 inches, and here again a reference to the measurements of growth (see page 69) indicates sufficient moisture for the needs of the trees. At the stations of Fort Collins, Colo., and Logan, Utah, the tree plats were irrigated, and were therefore inde- pendent of rainfall. SOIL AND SOIL, MOISTURE. The amount of rainfall is not necessarily an indication of the moisture of the soil, and hence of the amount of water available for the roots of the trees. A heavy rain might fall on compact, sun-baked soil, such as is common over extensive areas of the West, and by far the greater part of the water would run off and be lost to vegetation because the 19 character of the soil would not permit its absorption. Herein will be found one of the most helpful uses of groves in Western agriculture. The tree tops will protect the surface of the soil, which, after the few years' cultivation given the trees immediately following planting, will become much more absorptive than when protected only by the slight covering of grasses which nature has placed there. The annual crop of leaves falling in the grove becomes an additional absorbent, si\ '>, * "■ t. v •* « ■» V. ••o • * V.